The present invention relates generally to speed regulating devices for internal combustion engines and relates more particularly to a resilient drive for diesel engine fuel injection pump governors.
Fuel injection pump governors, although of various types, all include essentially a mechanism for sensing the speed of the engine, and means for adjusting the engine fuel control in response to speed changes. In a common form of governor for which the present invention has been developed, the engine speed is sensed mechanically, for example by a flyweight assembly, which assembly is mounted on a governor shaft which is rotated at a speed corresponding to engine speed. In a conventional installation, the governor shaft is gear driven from the fuel injection pump, the camshaft of which is coupled directly to the engine for rotation, typically at one half engine speed.
When the engine is running at a constant speed, the governor flyweights should also sense a constant speed and be extended in a stable attitude, operating against a spring force to provide a positioning of the governor linkage in a stable position commensurate with the engine speed. However, inherent in the injection pump drive train, due in large measure to the intermittent torsional forces required to actuate the fuel pumping mechanism, are instantaneous acceleration and deceleration effects which pass into the governor shaft and are sensed by the flyweight assembly. These torsional vibrations, known as "torsionals", interfere with the stability of the flyweights and governor linkage, in some cases causing a surging tendency of the governor. Torsionals also have a deleterious effect on the governor pivot points which tend to wear due to the constant chattering induced by the torsionals at these points.